                    FOR PUBLICATION

   UNITED STATES COURT OF APPEALS
        FOR THE NINTH CIRCUIT


 TUCKER DURNFORD,                             No. 16-15374
 individually and on behalf of
 all others similarly situated,                D.C. No.
               Plaintiff-Appellant,       3:15-cv-00413-HSG

                  v.
                                                OPINION
 MUSCLEPHARM CORP.,
         Defendant-Appellee.


       Appeal from the United States District Court
         for the Northern District of California
     Haywood S. Gilliam, Jr., District Judge, Presiding

         Argued and Submitted November 15, 2017
                 San Francisco, California

                    Filed October 12, 2018

   Before: Marsha S. Berzon and Michelle T. Friedland,
   Circuit Judges, and William K. Sessions III, * District
                          Judge.

                   Opinion by Judge Berzon

    *
      The Honorable William K. Sessions III, United States District
Judge for the District of Vermont, sitting by designation.
2                DURNFORD V. MUSCLEPHARM

                          SUMMARY **


       Preemption / Food, Drug, and Cosmetic Act

    The panel reversed the district court’s dismissal of an
action alleging California consumer claims against
MusclePharm Corporation, a manufacturer of nutritional
supplements, for making false or misleading statements
about the protein in one of its products; and remanded for
further proceedings.

    The district court dismissed the action as preempted by
the Food, Drug, and Cosmetic Act (“FDCA”), reasoning that
any declarations of protein content anywhere on a product
label could not be false or misleading if the listed amount of
protein reflected measurements made in accordance with
federal regulations concerning the federally mandated
nutrition panel.

    The panel held that, as relevant here, the FDCA and its
implementing regulations concerned only the calculation
and disclosure of protein amounts. Specifically, the panel
held that the FDCA preempted a state-law misbranding
theory premised on the supplement’s use of nitrogen-spiking
agents to inflate the measurement of protein for the nutrition
panel. The panel further held that the FDCA did not,
however, preempt a state-law misbranding theory premised
on the label’s allegedly false or misleading implication that
the supplement’s protein came entirely from two specifically
named, genuine protein sources. The panel concluded that

    **
       This summary constitutes no part of the opinion of the court. It
has been prepared by court staff for the convenience of the reader.
               DURNFORD V. MUSCLEPHARM                      3

plaintiff’s claims were not preempted to the extent they arose
under this theory.


                        COUNSEL

Matt J. Malone (argued), Susan F. Brown, and Michael F.
Ram, Ram Olson Cereghino & Kopczynski, San Francisco,
California, for Plaintiff-Appellant.

Michael J. Suffern (argued) and Linda E. Maichl, Ulmer &
Berne LLP, Cincinnati, Ohio, for Defendant-Appellee.


                         OPINION

BERZON, Circuit Judge:

    Tucker Durnford brought California consumer claims
against MusclePharm Corporation, a manufacturer of
nutritional supplements, for making false or misleading
statements about the protein in one of its products. The
district court dismissed Durnford’s action as preempted by
the Food, Drug, and Cosmetic Act (“FDCA”), 21 U.S.C.
§§ 301–399i, reasoning that any declarations of protein
content anywhere on a product label could not be false or
misleading if the listed amount of protein reflected
measurements made in accordance with federal regulations
concerning the federally mandated nutrition panel. We
disagree. As here relevant, the FDCA and its implementing
regulations concern only the calculation and disclosure of
protein amounts. They say nothing about the source or
composition of protein, factors which underlie one of
Durnford’s several theories of consumer deception.
4                 DURNFORD V. MUSCLEPHARM

Durnford’s claims are therefore not preempted to the extent
they arise under that theory.

                                   I

    MusclePharm is a Nevada corporation that produces a
line of nutritional supplements, including the “Arnold
Schwarzenegger Series Iron Mass” supplement (“the
Supplement”) here at issue. Durnford is a California citizen
who purchased the Supplement from a sports nutrition
retailer in 2014.

    The Supplement is marketed as a muscle-building or
weight-gain product, with a focus on its “revolutionary 5-
stage mass delivery system.”         According to the
                   1
Supplement’s label, this “system” consists of “advanced
protein technology, elite complex carbs, healthy fats,
cutting-edge performance ingredients and a balanced
digestive blend.”

    The label describes the “stages” of the Supplement’s
“system” in some detail. In particular, the second stage is
described as “Muscle plasma protein technology: 40g of a
potent blend of hydrolyzed beef protein and lactoferrin
protein.” The fourth stage is described as “Performance
growth & muscle volumizer: Creatine and BCAA nitrates
help promote muscular strength, size and endurance.”




    1
       We refer to the product’s packaging as a whole as the “label.” We
refer to the federally mandated declaration of nutritional content within
the label as the “nutrition panel.” As will be explained, the latter is
subject to a unique set of stringent federal regulations.
               DURNFORD V. MUSCLEPHARM                      5




    The nutrition panel at the back of the label also reflects
the “five-stage system.” For example, in listing the
Supplement’s ingredients, the front of the label divides
ingredients according to the “five stages.” The nutrition
panel then repeats the five stages in the same order they
appear on the front of the label, and repeats the same jargon
in describing them.
6              DURNFORD V. MUSCLEPHARM




      As should be apparent, the second group of ingredients
listed on the nutrition panel corresponds to the second stage
of the Supplement’s “system.” This group of ingredients is
described as the “Muscle Plasma Protein Matrix,” consisting
of “Hydrolyzed Beef Protein, Lactoferrin.” The fourth
group of ingredients listed on the nutrition panel corresponds
to the fourth stage of the Supplement’s system. This group
of ingredients is described as the “Performance Growth &
Muscle Volumizer,” consisting of “Creatine Monohydrate,
L-Glycine, BCAA Nitrates (Leucine, Iso-Leucine, Valine)
. . . , D-Ribose.” The nutrition panel states that a single
                   DURNFORD V. MUSCLEPHARM                                 7

serving of 95 grams of the Supplement contains 40 grams of
protein, or 72% of the recommended daily value.

    In January 2015, Durnford brought an action alleging
that MusclePharm had engaged in “protein spiking” or
“nitrogen spiking” — the practice of inflating measurements
of a supplement’s protein content using non-protein
substances — thereby rendering the Supplement falsely or
misleadingly labeled. 2 Specifically, Durnford alleged that
MusclePharm used creatine monohydrate and free-form
amino acids (l-glycine, leucine, iso-leucine, and valine) to
inflate protein figures. These are the substances that appear
at stage four of the Supplement’s “system.” Durnford also
alleged that an independent study of the Supplement
demonstrated that its true protein value was not 40 grams per
serving, but 19.4 grams per serving.

    Durnford brought claims under California’s Unfair
Competition Law (“UCL”), Cal. Bus. & Prof. Code
§§ 17200–17210; False Advertising Law (“FAL”), Cal. Bus.
& Prof. Code §§ 17500–17509; and Consumer Legal
Remedies Act (“CLRA”), Cal. Civ. Code §§ 1750–1784;
and for breach of express warranty. The express warranty
claim was premised on the theory that the Supplement’s
“labeling, marketing and advertising constitute express
warranties and became part of the basis of [the] bargain” —
a bargain struck, according to the complaint, “at the time
[consumers] purchased the Product.”


    2
      According to the complaint, because nitrogen is used as marker for
protein, manufacturers seeking a low-cost way of inflating their protein
figures are known to “spike” their formulations with nitrogen-rich
additives that provide little or none of the benefit of actual protein. Free-
form amino acids — amino acids that are not bound together in complex
chains, as proteins are — are sometimes used as nitrogen-spiking agents.
8              DURNFORD V. MUSCLEPHARM

    Durnford also alleged that, at some point, an individual
“tweeted at” MusclePharm’s official Twitter account to ask
about the truth behind product reviews accusing
MusclePharm of nitrogen spiking. MusclePharm responded
via Twitter: “Those [reviews] are fake then. We don’t do
anything like that. All products legit and scientifically
backed[.]” The individual who tweeted at MusclePharm
identified himself on Twitter as “Jacob Henderson.” The
complaint did not explain who Jacob Henderson was, what
relationship he had to Durnford or to this case, when the
Twitter interaction took place, or whether Durnford was
aware of it.

    Durnford did not explain his reasons for purchasing the
Supplement. For example, he did not allege that he
purchased the product intending to gain weight or add
muscle, the likely reason for most purchases of the product.
He did state, however, that he “would not have purchased
the Supplement had [he] known the true nature of the protein
content.”     And he alleged that he “purchased the
[Supplement] in reliance on [MusclePharm’s] labeling and
marketing claims.”

    MusclePharm moved to dismiss the complaint on
preemption grounds, for failure to plead reliance adequately,
and for failure to plead fraud with particularity. In granting
the motion to dismiss, the district court divided Durnford’s
four legal claims into three theories of misrepresentation,
each tied to one of MusclePharm’s “claims” about its
product. The “Protein Content Claim” referred to the theory
that Durnford was misled by the 40-gram figure on the
Supplement’s nutrition panel, as independent testing
allegedly revealed that figure to be heavily influenced by
nitrogen-rich non-protein substances such as free-form
amino acids. The “Protein Composition Claim” referred to
                  DURNFORD V. MUSCLEPHARM                               9

the theory that Durnford was misled by the label’s
suggestion that the product contained 40 grams of protein
derived entirely from hydrolyzed beef protein and lactoferrin
rather than nitrogen-spiking agents. The “Nitrogen Spiking
Claim” referred to the theory that Durnford was misled by
the statement MusclePharm made on its Twitter account in
response to a direct question about nitrogen spiking.

    The district court ruled for MusclePharm on preemption
grounds with respect to the “Protein Content Claim.”
Specifically, the court noted that Food and Drug
Administration (“FDA”) regulations allow a manufacturer to
use nitrogen content as a proxy for protein content, thus
permitting the practice of nitrogen spiking. 3 As the FDCA
expressly preempts state-law requirements that are “not
identical to” those in the FDCA itself, 21 U.S.C. § 343-
1(a)(5), the district court concluded that even if the label
might be considered misleading, California consumer law
could not be used to create liability for an FDA-compliant
measurement.

    The district court ruled for MusclePharm on the “Protein
Composition Claim” on preemption grounds as well, but on
narrower reasoning. The court accepted the theory that
MusclePharm’s label falsely or misleadingly suggested that
the Supplement contained 40 grams of protein derived
entirely from hydrolyzed beef protein and lactoferrin and
therefore not from nitrogen spiking. The court also accepted
that a misbranding theory of that kind went beyond a claim

    3
       The Secretary of Health and Human Services (“HHS”) has
“authority to promulgate regulations for the efficient enforcement of” the
FDCA. 21 U.S.C. § 371(a). The agency within HHS responsible for
FDCA regulations is the FDA. We therefore refer to the relevant
regulations in this case as “FDA regulations.”
10             DURNFORD V. MUSCLEPHARM

based purely on the FDA’s approved methods of calculating
protein content. Nonetheless, the district court concluded
that Durnford’s claims, “as currently pled, are preempted,”
as Durnford did not allege that his independent study
demonstrating a lack of true protein “conformed to the
[FDA] requirements” for measuring protein content.

    Finally, the district court ruled for MusclePharm on its
“Nitrogen Spiking Claim” for failure to plead reliance
adequately, a problem the court described as a lack of
statutory standing under California’s consumer protection
laws. The court noted that it could be “reasonable to
presume that consumers read and rely on product labels
when purchasing a supplement.” But the court was unable
to draw such an inference regarding the comment made on
Twitter.

    The district court dismissed the complaint without
prejudice to repleading to cure the preemption and reliance
problems. Durnford allowed the period for amendment to
lapse, and the court entered judgment. This appeal followed.

                              II

    We begin with a review of federal preemption under the
relevant provision of the FDCA. The FDCA provides, in
relevant part, that

       no State . . . may directly or indirectly
       establish under any authority or continue in
       effect as to any food in interstate commerce
       . . . (4) any requirement for nutrition labeling
       of food that is not identical to the requirement
       of section 343(q) of this title . . . or, (5) any
       requirement respecting any claim . . . made in
       the label or labeling of food that is not
                    DURNFORD V. MUSCLEPHARM                             11

           identical to the requirement of section 343(r)
           of this title. 4

21 U.S.C. § 343-1(a) (emphases added). 5 Section 343(q)
addresses the information that must be disclosed in a
nutrition panel under the FDCA. See 21 U.S.C. § 343(q)(1),
(q)(5)(F); Revision of the Nutrition and Supplement Facts
Labels, 81 Fed. Reg. 33,742, 33,744 (May 27, 2016). As
here relevant, the section provides that food is deemed
“misbranded” unless its nutrition panel includes a statement
of the product’s “total protein.” 21 U.S.C. § 343(q)(1)(D).

    FDA regulations provide guidance as to the acceptable
means of calculating “total protein” for purposes of the
mandatory nutrition panel. Specifically, “[p]rotein content
may be calculated on the basis of the factor 6.25 times the
nitrogen content of the food as determined by the appropriate
method of analysis . . . .” 21 C.F.R. § 101.9(c)(7). This
regulation applies equally to ordinary food and to dietary
supplements, “except that [for dietary supplements] the
sample for analysis shall consist of a composite of
12 subsamples (consumer packages) or 10 percent of the
number of packages in the same inspection lot, whichever is
smaller, randomly selected to be representative of the lot.”
21 C.F.R. § 101.36(f)(1).

    Section 343(r) addresses statements concerning
nutritional content other than those required to be included

    4
        Both section references are to title 21 of the United States Code.

    5
       This section and the sections cited within it were added to the
FDCA in 1990 in the Nutrition Labeling and Education Act (“NLEA”),
Pub. L. No. 101-535, 104 Stat. 2353 (Nov. 8, 1990). For simplicity, we
refer to the NLEA provisions as part of the FDCA except as necessary
to distinguish them.
12                DURNFORD V. MUSCLEPHARM

in the nutrition panel. As relevant here, the section provides
that products whose labels “characterize[] the level of any
nutrient” listed in section 343(q) are deemed misbranded
unless they comply with specific requirements, established
by regulation, for nutrient disclosures of that kind. 21 U.S.C.
§ 343(r)(1)–(2). A separate provision of the FDCA provides
another, broader description of misbranding. According to
section 343(a), “food shall be deemed to be misbranded . . .
[if] its labeling is false or misleading in any particular.”
21 U.S.C. § 343(a).

    The FDA has promulgated regulations attempting to
clarify the scope of express preemption under the “not
identical to” standard stated in section 343-1(a). According
to the FDA, in preempting state law that would impose
requirements “not identical to” those in the FDCA, the
statute is not concerned with “the specific words in the
[state-law] requirement.” 21 C.F.R. § 100.1(c)(4). Instead,
the federal statute displaces “obligations or . . . provisions
concerning the composition or labeling of food . . . [that]
[a]re not imposed by or . . . [that] [d]iffer from those
specifically imposed by” the FDCA. 6               21 C.F.R.
§ 100.1(c)(4)(i)–(ii).

    FDCA preemption is subject to well-established limiting
principles. First, federal preemption arising from the
provisions at issue in this case is, by statutory prescription,
express preemption only. See NLEA § 6(c)(1), 104 Stat. at

     6
       In the absence of a specific congressional delegation of authority
to interpret the scope of preemption, agency interpretations regarding the
scope of preemption are not entitled to deference under Chevron, U.S.A.,
Inc. v. Nat. Res. Def. Council, Inc., 467 U.S. 837 (1984). See Wyeth v.
Levine, 555 U.S. 555, 576 (2009). Durnford has not, however,
challenged the FDA’s interpretation of the preemptive effect of the
FDCA, so we assume its applicability.
               DURNFORD V. MUSCLEPHARM                    13

2364 (codified at 21 U.S.C. § 343-1 note) (“The [NLEA]
shall not be construed to preempt any provision of State law,
unless such provision is expressly preempted under [section
343-1].”); Hawkins v. The Kroger Co., No. 16-55532, slip
op. at 8 (9th Cir. Oct. 4, 2018) (citing Reid v. Johnson &
Johnson, 780 F.3d 952, 959 (9th Cir. 2015)). Second, a
presumption against preemption applies to the extent the
FDCA is used to displace state law in an area of traditional
state police power. See Wyeth v. Levine, 555 U.S. 555, 565
& n.3 (2009); Holk v. Snapple Beverage Corp., 575 F.3d
329, 334–35 (3d Cir. 2009). Consumer protection falls well
within that category. See Medtronic, Inc. v. Lohr, 518 U.S.
470, 485 (1996).

                            III

   We turn now to review of the order granting
MusclePharm’s motion to dismiss. Our review is de novo.
Edwards v. Marin Park, Inc., 356 F.3d 1058, 1061 (9th Cir.
2004). The district court’s three-part categorization of
Durnford’s claims is a useful framework for evaluating
Durnford’s theories of misbranding, so we adhere to it.

                             A

    The “protein content” theory of misbranding refers to
Durnford’s allegations that he was misled by the 40-gram
figure on the Supplement’s nutrition panel, because it was a
product of nitrogen spiking and so not an accurate
measurement of true protein content. This theory is
foreclosed by the FDCA.

    The FDCA requires the disclosure of the    “amount” of
“total protein” in the nutrition panel,         21 U.S.C.
§ 343(q)(1)(D), and FDA regulations approve    of the use of
nitrogen as a proxy in complying with that     requirement,
14             DURNFORD V. MUSCLEPHARM

21 C.F.R. § 101.9(c)(7). These regulations have the same
preemptive effect as a statute, Fidelity Fed. Sav. & Loan
Ass’n v. de la Cuesta, 458 U.S. 141, 153–54 (1982), and so
foreclose the possibility of liability under state law for
nitrogen spiking.

    Durnford argues otherwise, maintaining that the
regulation serves internal “regulatory” purposes and is not
intended to have preemptive effect. But the regulation is not
just an internal guidance; it is an interpretation of the
statutory provision requiring that manufacturers disclose a
product’s protein content, a concept that requires federal
agency clarification if there is to be national uniformity in
labeling. See Reid, 780 F.3d at 959. Where, as here,
“Congress has ‘explicitly left a gap for an agency to fill,
there is an express delegation of authority to the agency to
elucidate a specific provision of the statute by regulation,’
and any ensuing regulation is binding unless . . . defective.”
United States v. Mead Corp., 533 U.S. 218, 227 (2001)
(Chevron U.S.A. Inc. v. Nat. Res. Def. Council, Inc.,
467 U.S. 837, 843–44 (1984)).

    Astiana v. Hain Celestial Grp., Inc., 783 F.3d 753 (9th
Cir. 2015), is consistent with this conclusion. Astiana held
that a state law challenge to a cosmetic labeled “natural” was
not preempted because “Astiana [was] not asking [the
manufacturer] to modify or enhance any aspect of its
cosmetics labels that are required by federal law.” Id. at 758.
No statute or regulation governed “the use of ‘natural’ on
cosmetics labels.” Id. There was therefore no basis for
express preemption in Astiana. Not so here, where
disclosure of the amount of protein content on the nutrition
panel is required by statute, and the proper means of
calculating that amount is set out in the regulation.
                  DURNFORD V. MUSCLEPHARM                            15

    That section 343(a) prohibits false or misleading
statements in general does not alter our analysis. Durnford
has not on appeal challenged as invalid the FDA regulation
allowing the use of nitrogen content as a proxy for protein.
He does not argue, for example, that the agency has
authorized, by regulation, an inherently misleading means of
calculating protein, such that it has exceeded its
congressionally delegated authority in light of section
343(a). See Chevron, 467 U.S. at 843; see also Mead,
533 U.S. at 227. Any such argument is thus forfeited. 7 See
Smith v. Marsh, 194 F.3d 1045, 1052 (9th Cir. 1999).

    Durnford’s remaining arguments against preemption are
without merit. Durnford misreads the FDA’s protein
regulation as precluding the use of nitrogen as a benchmark
when calculating a percentage of recommended daily value.
The regulation provides only that, if a percentage of
recommended daily value is declared on the nutrition panel,
it should be calculated using the “corrected amount of
protein per serving.” 21 C.F.R. § 101.9(c)(7)(i). The
corrected amount of protein per serving “is equal to the
actual amount of protein . . . per serving [in grams]
multiplied by the amino acid score corrected for protein
digestibility.” 21 C.F.R. § 101.9(c)(7)(ii). The “correction”
is therefore not to remove nitrogen-spiking agents, as
Durnford suggests, but to account for digestibility. This
digestibility correction has no apparent impact on the
validity of the MusclePharm label, nor has Durnford
suggested any. And although Durnford notes that a separate
regulation states that “[p]rotein shall not be declared on
labels of products that, other than ingredients added solely
for technological reasons, contain only individual amino

    7
      As the nitrogen-as-protein regulation has not been challenged, this
opinion should not be taken as either approving it or disapproving it.
16             DURNFORD V. MUSCLEPHARM

acids,” the Supplement is not such a product. 21 C.F.R.
§ 101.36(b)(2)(i) (emphasis added). It contains more than
just individual amino acids.

    In sum, federal regulations allow nitrogen to be used on
the nutrition panel as a proxy for protein content.
Accordingly, a state-law misbranding claim premised on
nitrogen spiking — that is, a claim that would permit a state
to impose requirements for the measurement of protein for
purposes of the federal mandated nutrition panel different
from those permitted under the FDCA — is preempted.

                             B

     Durnford’s “protein composition” theory of misbranding
is that the Supplement’s label misled him into believing the
Supplement’s protein came entirely from genuine protein
sources — hydrolyzed beef protein and lactoferrin — rather
than nitrogen-spiking agents. The district court accepted the
possibility that the label created a false or misleading
impression in this respect. The district concluded, however,
that Durnford’s claims were nonetheless preempted because
he did not allege that he had any independent study
contradicting the label that used the FDA’s elaborate 12-
sample testing protocol. See 21 C.F.R. § 101.36(f)(1).

    This reasoning misapprehends Durnford’s protein
composition theory. That theory rests not on the misleading
nature of nitrogen spiking but on the label’s misleading
suggestion that all of the protein in the Supplement, in
whatever amount it exists, comes from specific protein
sources. In other words, Durnford’s argument goes not to
the amount of protein, but to its composition. The FDA’s
testing protocol is relevant only to the former.
                   DURNFORD V. MUSCLEPHARM                               17

    As an initial matter, the premise behind the protein
composition theory is correct. The label — separately from
the mandatory nutrition panel — twice identifies hydrolyzed
beef protein and lactoferrin as the protein sources in the
Supplement. The label then apparently distinguishes those
protein sources from nitrogen compounds, which are listed
and identified separately not as protein, but as “performance
growth and muscle volumizer.” The label further states that
the Supplement’s proteins are present in the amount of “40g
of a . . . blend of . . . beef protein and lactoferrin” — the same
amount of protein claimed per serving on the nutrition panel.
Finally, in its ingredients list, the label repeats the distinction
in nomenclature between true proteins and other substances,
referring to hydrolyzed beef protein and lactoferrin part of
the Supplement’s “protein technology,” and calling the free-
form amino acids “muscle volumizer.”

    Under Durnford’s theory of misbranding, whether or not
there was compliance with the FDA’s 12-sample testing
protocol does not matter. 8 The disputed testing protocol is a

    8
       We need not address whether plaintiffs are ever required to allege,
at the pleading stage, that there are tests contradicting the nutrition panel
that comply with the FDA’s testing protocols. We note, however, that
plaintiffs are generally not expected to provide evidence in support of
their claims at the pleading stage, see Cafasso, U.S. ex rel. v. Gen.
Dynamics C4 Sys., Inc., 637 F.3d 1047, 1055 (9th Cir. 2011), nor are
they required to plead the “probability” of their entitlement to relief,
Ashcroft v. Iqbal, 556 U.S. 662, 678 (2009). In addition, FDCA
preemption, like all federal preemption, is an affirmative defense.
Lusnak v. Bank of Am., N.A., 883 F.3d 1185, 1194 n.6 (9th Cir. 2018).
“Only when the plaintiff pleads itself out of court — that is, admits all
the ingredients of an impenetrable defense — may a complaint that
otherwise states a claim be dismissed under Rule 12(b)(6).” Xechem,
Inc. v. Bristol-Myers Squibb Co., 372 F.3d 899, 901 (7th Cir. 2004); see
also Scott v. Kuhlmann, 746 F.2d 1377, 1378 (9th Cir. 1984) (per
curiam).
18                 DURNFORD V. MUSCLEPHARM

requirement for “[c]ompliance with this section,” 21 C.F.R.
§ 101.36(f)(1) — that is, for compliance with the section of
FDA regulations determining the proper means of
calculating protein content in dietary supplements. See also
21 C.F.R. § 101.9(g). But Durnford’s protein composition
theory is not concerned with the total amount of protein in
the Supplement; it is concerned with the source of that
protein. Durnford argues that, whatever the true protein
amount in grams per serving, the label falsely or
misleadingly suggested that that protein is entirely
composed of two kinds of actual, genuine protein. In other
words, according to Durnford, the label falsely disclaims
nitrogen spiking.

    In sum, Durnford’s complaint adequately alleges facts
necessary to support a consumer claim premised on his
protein composition theory of misbranding. 9 As noted,
Durnford brought three California statutory claims, as well
     9
        MusclePharm argues that lack of reliance offers an alternative
ground for affirmance, at least as to the three statutory claims. See
Kwikset Corp. v. Superior Court, 51 Cal. 4th 310, 326 (2011).
MusclePharm notes, correctly, that the complaint makes sparse, generic
allegations regarding Durnford’s reliance on the Supplement’s label, and
fails to explain Durnford’s reasons for purchasing the product. But the
district court declined to address this issue, and speculated that an
inference of reliance might be reasonable under the circumstances. We
decline to reach the question of reliance in the first instance, particularly
as the district court retains the discretion, on remand, to grant the
plaintiffs leave to amend the complaint so as better to allege reliance on
the misbranding.

     MusclePharm also argues that failure to plead fraud with
particularity is an alternative ground for affirmance. But apart from a
possible reliance problem, the “who, what, when, where, and how”
required by Federal Rule of Civil Procedure 9(b) are evident in the
allegations supporting Durnford’s protein composition theory. See
Kearns v. Ford Motor Co., 567 F.3d 1120, 1124 (9th Cir. 2009).
               DURNFORD V. MUSCLEPHARM                    19

as a claim for breach of express warranty. MusclePharm has
made no attempt on appeal to distinguish between the
elements of these nominally distinct legal claims for
purposes of the protein composition theory, and there is no
evident difference. Durnford’s protein composition theory
is therefore ground for reversal as to all claims.

                             C

    Finally, the so-called “Nitrogen Spiking Claim” refers to
the theory that Durnford was misled by a tweet from
MusclePharm stating that it did not use nitrogen-spiking
agents to inflate its protein figures. But nothing in the
complaint connects this tweet to Durnford’s purchase of the
Supplement. To the extent Durnford intended the tweet as
an independent basis for his claims — rather than simply as
illustrative evidence of the way MusclePharm intended its
consumers to understand the composition of the Supplement
— the complaint is inadequate.

                             IV

    The FDCA, in light of its implementing regulations,
preempts a misbranding theory premised on the
Supplement’s use of nitrogen-spiking agents to inflate the
measurement of protein for the nutrition panel. It does not,
however, preempt a misbranding theory premised on the
label’s allegedly false or misleading implication that the
Supplement’s protein came entirely from two specifically
named, genuine protein sources. The district court’s order
of dismissal is REVERSED, and this case is REMANDED
for further proceedings consistent with this opinion.
