B12 and L-carnitine are on the Peptides+ list. They also have the longest FDA track record of the bunch

By · Published · 7 min read · 14 sources, 13 checked at the source

AI-generated editorial illustration: a marble kitchen counter with small bottles labeled L-Carnitine and Vitamin B12, a stethoscope, a bowl of eggs and a bunch of greens.

When Hims & Hers previewed its Peptides+ offering on October 29, 2026, two of the five names on its list were ones your grandparents might recognize: vitamin B12 and L-carnitine. [V] They sat right next to sermorelin, glutathione and NAD+, with BPC-157 and TB-500 promised for later. [V] Here's the fun twist. Neither B12 nor L-carnitine is a peptide, and both have something most of the buzzier names on that list don't: an FDA-approved prescription drug with decades of history behind it. [V] So what do they actually do, what does the research show, and where do they stand with FDA?

Facts are as of November 11, 2026. Sources, with retrieval dates, are at the bottom.

The short version

  • L-carnitine is built from amino acids and shuttles fat into your cells' mitochondria to be burned for energy. FDA approved it as the prescription drug Carnitor in 1985. [V]
  • In pooled randomized trials, L-carnitine was linked to modest extra weight loss and less post-workout muscle soreness. Results on athletic performance are mixed. [V]
  • Vitamin B12 is a cobalt-containing vitamin your nerves and red blood cells depend on. It comes as food, supplements and prescription drugs, including an FDA-approved nasal spray. [V]
  • B12 clearly matters when you're low, and plenty of adults are. NIH says extra B12 doesn't appear to boost performance in people who already have enough. [V]

Why these two are on a peptide menu

Peptides+ is a program name, not a chemistry lesson. Hims's own preview pitches it as care at "a cellular level," covering needs from energy to recovery, and its launch list mixes true peptides with a coenzyme (NAD+), a vitamin (B12) and an amino-acid derivative (L-carnitine). [V] That mix makes sense for a wellness lineup. On the November 9 earnings call, the company said the first phase arrives later this month with sermorelin, glutathione and NAD, and B12 came up in the Q&A, according to a third-party transcript. [S] Our Peptides+ launch story covers the full rollout, and our side-by-side guide covers the first three names.

L-carnitine: the fat-shuttle molecule

Carnitine is really a small family: L-carnitine plus two close relatives, the acetyl and propionyl forms. It's made from amino acids, so it's a cousin of peptides rather than one of them. [V] Its job is elegant: it carries long-chain fatty acids into the mitochondria, where they're burned to make ATP, the cell's energy currency. [V] About 95% of the body's carnitine sits in the heart and skeletal muscle, which is exactly why fitness culture got interested. [V] Healthy people make enough on their own, and meat and dairy add more. [V]

The research record is bigger than many people expect. Here's what the pooled trials found:

  • Weight. A 2016 meta-analysis of 9 randomized trials with 911 adults found people taking carnitine lost about 1.3 kg more than controls, though the effect shrank the longer studies ran. [V] A larger 2020 meta-analysis of 37 randomized trials with 2,292 people found modest drops in body weight, BMI and fat mass, but no change in waist size or body fat percentage. Its authors saw the clearest effect in adults with overweight or obesity. [V] (Meta-analyses of randomized trials.)
  • Muscle soreness. A 2020 meta-analysis of 7 randomized trials found L-carnitine eased delayed-onset muscle soreness for up to four days after exercise and lowered blood markers of muscle damage. The benefit showed up mainly in resistance-training groups and untrained people. [V] (Meta-analysis of small randomized trials.)
  • Performance. NIH's fact sheet calls the evidence on athletic performance mixed. Some studies found gains in strength work, while others found no change in endurance measures, and none found better moderate-intensity performance. [V]

Vitamin B12: small molecule, big job

B12 has a metal at its center. It contains cobalt, which is why its forms are called cobalamins. [V] Your body needs it to build healthy red blood cells, make DNA and keep the nervous system working, including the myelin that insulates nerves. [V] Methylcobalamin and adenosylcobalamin are the active forms; cyanocobalamin and hydroxocobalamin get converted into them. [V]

The strongest evidence for B12 is about not running low, and running low is more common than you'd think. NIH says somewhere between 3% and 43% of older adults living at home are deficient, depending on the definition used. [V] People at higher risk include those with pernicious anemia, people who've had stomach or bowel surgery (weight-loss surgery included), long-term users of metformin or acid-reducing proton pump inhibitors, and vegans. [V] Fatigue is one of the classic signs of deficiency, along with anemia and numbness or tingling. [V] That's where B12's reputation as an energy vitamin comes from. For people who already have enough, NIH says supplements don't appear to improve performance or endurance. [V]

Where they stand with FDA

This is where these two stand apart from most names in the peptide conversation. Both are ingredients in FDA-approved drugs. [V]

L-carnitineVitamin B12
What it isAmino-acid derivative, not a peptide [V]Cobalt-containing vitamin, not a peptide [V]
FDA-approved drug?Yes: Carnitor tablets and solution (1985), Carnitor IV form (1992), plus many generics [V]Yes: prescription cyanocobalamin products, including the Nascobal nasal spray (2005) [V]
Also sold as a supplement?Yes [V]Yes [V]
FDA compounding listsLevocarnitine flagged as a component of an approved drug; acetyl-L-carnitine in 503ASection of federal drug law covering compounding by state-licensed pharmacies and doctors, usually for a prescription written for one patient. Glossary entry category 1 (under evaluation) [V]Cyanocobalamin and hydroxocobalamin flagged as components of approved drugs; methylcobalamin in 503A category 1 [V]
In the HHS six-peptide draft?No [V]No [V]

That compounding row matters. Under section 503A of the federal drug law, a pharmacy can compound from a bulk ingredient that meets a USP monograph, or, if no monograph exists, one that's a component of an FDA-approved drug. Only after those does the 503A bulks list come in. [V] So the approved forms of these two have a more established path than BPC-157 or TB-500, which rely on HHS's draft enforcement-discretion policy. [V] Our compounding categories guide explains the three categories, and our 503A bulks list explainer covers how a substance gets on the list.

Limits and unknowns

  • The L-carnitine and heart question. In a 2013 Nature Medicine study, gut bacteria turned dietary L-carnitine into TMAO, a compound that sped up artery plaque in mice. Meat eaters made more TMAO than vegans. In 2,595 people having heart checkups, higher blood carnitine was tied to heart and artery disease risk, but only in people who also had high TMAO. [V] NIH says what this means for people isn't well understood yet. [V] (Mouse study plus observational human data.)
  • Drug interactions. NIH lists medicines that can interact with carnitine, including pivalate-containing antibiotics, and says people on regular medications should check with their clinician. [V]
  • Small effects. The weight results are real but modest, and many trials were small or short. [V]
  • B12 is gentle, but not a cure-all. NIH says no upper intake limit was set because toxicity risk is low. [V] A normal level, though, means more B12 isn't an energy fix, and fatigue has many causes worth checking. [U]

Peptide Policy Watch

B12 and L-carnitine are on the Peptides+ list. They also have the longest FDA track record of the bunch

Published November 11, 2026 · https://peptidepolicywatch.com/2026/11/11/b12-l-carnitine-peptides-plus-research-fda-status/

Printable checklist

Bring these to your next checkup

Points from this story to talk through with a clinician or pharmacist who knows your history.

  1. Should my B12 level be checked, given my diet and the medicines I take?
  2. If a carnitine product is suggested, is it the FDA-approved levocarnitine or a supplement?
  3. Does carnitine interact with anything I'm on now?
  4. If I'm tired a lot, what else should we rule out first?

Print view Select it, then use your browser’s Print command to print only this box.

B12 and L-carnitine may be the least flashy names on the Peptides+ list. They're also the two with the deepest research files and the clearest FDA footing, which is a pretty good place to start if you're curious.

Sources (retrieved November 11, 2026)

  1. Hims & Hers, "Expanding Safe Access to Peptides," newsroom post, October 29, 2026 [V] — https://news.hims.com/newsroom/expanding-safe-access-to-peptides
  2. Hims & Hers Q3 2026 earnings call, November 9, 2026, third-party transcript (Benzinga) [S] — https://www.benzinga.com/news/26/11/63076365/hims-hers-health-q3-2026-earnings-call-transcript
  3. NIH Office of Dietary Supplements, Carnitine fact sheet for health professionals, updated April 17, 2023 [V] — https://ods.od.nih.gov/factsheets/Carnitine-HealthProfessional/
  4. NIH Office of Dietary Supplements, Vitamin B12 fact sheet for health professionals, updated July 2, 2025 [V] — https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
  5. Pooyandjoo M et al., "The effect of (L-)carnitine on weight loss in adults: a systematic reviewA review that collects studies on one question by a stated search method, often pooling their numbers. Glossary entry and meta-analysis of randomized controlled trials," Obesity Reviews, 2016, PMID 27335245 [V] — https://pubmed.ncbi.nlm.nih.gov/27335245/
  6. Talenezhad N et al., "Effects of l-carnitine supplementation on weight loss and body composition," Clinical Nutrition ESPEN, 2020, PMID 32359762 [V] — https://pubmed.ncbi.nlm.nih.gov/32359762/
  7. Yarizadh H et al., "The Effect of L-Carnitine Supplementation on Exercise-Induced Muscle Damage," Journal of the American College of Nutrition, 2020, PMID 32154768 [V] — https://pubmed.ncbi.nlm.nih.gov/32154768/
  8. Koeth RA et al., "Intestinal microbiota metabolism of L-carnitine, a nutrient in red meat, promotes atherosclerosis," Nature Medicine, 2013, PMID 23563705 [V] — https://pubmed.ncbi.nlm.nih.gov/23563705/
  9. openFDA Drugs@FDA, Carnitor (levocarnitine) NDA 018948, original approval December 27, 1985, and NDA 020182, December 16, 1992 [V] — https://api.fda.gov/drug/drugsfda.json?search=openfda.brand_name:CARNITOR
  10. openFDA Drugs@FDA, Nascobal (cyanocobalamin) nasal spray NDA 021642, original approval January 31, 2005 [V] — https://api.fda.gov/drug/drugsfda.json?search=openfda.brand_name:NASCOBAL
  11. FDA, Bulk Drug Substances Nominated for Use in Compounding Under Section 503A (Categories 1-3), updated May 14, 2026 [V] — https://www.fda.gov/media/94155/download
  12. FDA, Bulk Drug Substances Nominated for Use in Compounding Under Section 503BSection of federal drug law for outsourcing facilities: larger compounders that register with FDA and must follow drug-manufacturing quality rules. Glossary entry (Categories 1-3), updated March 21, 2025 [V] — https://www.fda.gov/media/94164/download
  13. 21 U.S.C. 353a(b)(1)(A), pharmacy compounding (section 503A), via Cornell LII [V] — https://www.law.cornell.edu/uscode/text/21/353a
  14. HHS, "Enforcement Discretion Policy Regarding 503A Compounding Using Certain Peptide Bulk Drug Substances," October 28, 2026 [V] — https://www.hhs.gov/sites/default/files/hhs-503a-peptide-enforcement-discretion-policy-appendix-b.pdf
Cite or link to this page

Peptide Policy Watch staff. “B12 and L-carnitine are on the Peptides+ list. They also have the longest FDA track record of the bunch.” Peptide Policy Watch. Published November 11, 2026. https://peptidepolicywatch.com/2026/11/11/b12-l-carnitine-peptides-plus-research-fda-status/

Link: https://peptidepolicywatch.com/2026/11/11/b12-l-carnitine-peptides-plus-research-fda-status/

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