CVS now restricts melatonin to 18+. Illinois, New York, and California have introduced bills requiring pharmacy-counter placement. Australia issued a safety warning on melatonin gummies. This is changing how brands source sleep ingredients.
1. Why Retail Gatekeeping Matters for Sleep Ingredients
The sleep supplement category is being reshaped by a force that has nothing to do with efficacy data or consumer trends. It is being reshaped by retail gatekeeping.
In November 2023, CVS became the first major US retailer to restrict melatonin sales to buyers 18+. Illinois, New York, and California have since introduced state-level legislation requiring age verification or pharmacy-counter placement for melatonin products. Australia's drug regulator, the Therapeutic Goods Administration (TGA), issued a formal safety warning on melatonin gummies in October 2025 (Nogrady, BMJ 2025, PMID: 41057154). The UK classifies melatonin as prescription-only. The EU permits low-dose melatonin (1–2 mg) as a supplement in some member states while requiring a prescription in others.
What you'll learn in 6 minutes: where melatonin faces retail friction, what glycine's evidence actually supports, a 5-dimension procurement framework, and a supplier evaluation checklist.
2. Where Melatonin Wins — And Where Friction Is Emerging
Melatonin's Strengths
- Deepest clinical evidence base: hundreds of RCTs across decades of research
- Strong consumer name recognition — the default sleep supplement for most shoppers
- Proven efficacy for circadian-phase disorders (jet lag, shift work, delayed sleep phase)
- Established global supply chains with multiple qualified manufacturers
- Low active-ingredient cost per serving
Emerging Friction Points
1. Pediatric ingestion data. CDC surveillance (Lelak et al., MMWR, 2022, PMID: 35653284) documented a 530% increase in pediatric melatonin ingestion reports from 2012–2021, totaling 260,435 cases with two deaths and five children requiring mechanical ventilation. This data is being cited in state-level legislative proposals.
2. Retail response. CVS's voluntary 18+ restriction, combined with state-level legislative activity, suggests that retail access for melatonin may face incremental tightening — particularly for gummy formats marketed in mass retail channels.
3. International regulatory divergence. The TGA's 2025 safety warning on melatonin gummies follows a broader pattern: the UK classifies melatonin as prescription-only, EU member states apply inconsistent standards, and countries outside the US are increasingly treating melatonin as a controlled substance.
4. Label accuracy concerns. A JAMA analysis (Cohen et al., 2023, PMID: 37097362) tested 25 melatonin gummy products and found 22 deviated from label claims, with one product measured at 347% of declared content. This creates downstream procurement complexity: retailer QA departments are tightening documentation requirements.
3. What Retail Gatekeeping Means for Product Strategy
Shelf access is a primary driver of impulse purchases and trial volume in the sleep supplement category. When a product moves behind a pharmacy counter or behind an age gate, it loses a measurable portion of the 18–35 demographic that drives category growth. This is not speculation; it is retail math.
The label accuracy overhang adds a second layer: even in jurisdictions where melatonin remains on open shelves, the compliance burden is increasing. For procurement teams, this translates to:
- Additional third-party testing costs per batch
- Longer lead times for retailer onboarding
- Higher documentation overhead for distributor and retailer QA systems
- Increased exposure to class-action risk in the event of a label-accuracy dispute
4. Glycine: A Complementary Sleep Ingredient
Regulatory Profile
Glycine is GRAS (US), E640 (EU), and classified as a food-grade amino acid in most jurisdictions. Glycine-based sleep products face no pharmacy restrictions, no age limits, and no specific adverse-event reporting requirements. This translates to open shelf access across all retail formats: grocery, mass market, convenience, e-commerce.
What this means in practice: a glycine-based sleep product can be placed in any channel your brand targets, without the access constraints that are emerging for melatonin-based products in certain retail environments. This is a channel strategy advantage, not a clinical claim.
Clinical Evidence: What It Supports — And What It Does Not
A 2024 systematic review of 52 human studies (Soh et al., GeroScience, PMID: 37851316) confirmed that longer-term glycine administration improved subjective sleep quality in healthy populations. The review positioned glycine's sleep effects within its role as an inhibitory neurotransmitter and NMDA co-agonist — a mechanism fundamentally different from melatonin's hormonal pathway.
A randomized, double-blind crossover trial (Thomas et al., 2024, PMID: 37874350) found that glycine-rich collagen peptides reduced sleep fragmentation and improved next-morning cognitive performance in physically active males (awakenings: 21.3 vs 29.3, P=0.028; Stroop test: P=0.009).
Positioning: Differentiation, Not Superiority
Glycine's mechanism — NMDA receptor activation in the suprachiasmatic nucleus, triggering vasodilation that lowers core body temperature — does not involve hormonal modulation. This mechanistic distinction is a genuine positioning asset for a specific consumer segment: health-conscious buyers who prefer not to manipulate their hormonal axis for daily-use supplements.
| Recommended | Avoid | |
|---|---|---|
| Mechanism | "Non-hormonal sleep support" | "Better than melatonin" |
| Evidence | "Supported by emerging clinical evidence" | "Clinically proven for sleep" |
| Channel | "Open shelf access in all retail formats" | "Melatonin is losing shelf space" |
5. Q&A: What Procurement Teams Are Asking
Q: What does the current evidence base actually support for glycine and sleep?
The evidence supports glycine's role in improving subjective sleep quality and reducing sleep fragmentation at doses of approximately 3 g before bedtime. The Soh et al. (2024) systematic review, covering 52 human studies, confirmed these effects in healthy populations while noting the need for larger RCTs.
Q: How should brands position glycine relative to melatonin in retail?
The positioning opportunity is not "glycine replaces melatonin" but rather "glycine serves a different consumer need state." Melatonin consumers are seeking circadian-phase intervention. Glycine consumers are seeking relaxation and sleep onset support without hormonal modulation.
Q: Is glycine's regulatory profile strong enough to build a product line around?
Yes, with the right framing. Glycine's GRAS/E640 status provides a stable regulatory foundation. The key limitation is not regulatory — it is the depth of sleep-specific clinical data. Brands entering the glycine sleep space now are in an early-mover position.
6. A Procurement Framework for Sleep Ingredient Selection
| Dimension | What to Evaluate | Key Question |
|---|---|---|
| 1. Retail Channel Access | Age restrictions, pharmacy-counter requirements, open-shelf eligibility | Can the ingredient be placed in the retail formats that drive your volume? |
| 2. Regulatory Trajectory | Pending legislation, international divergence, pharmacopeia revisions | Is the regulatory environment becoming more or less permissive? |
| 3. Evidence Depth | RCT count, systematic reviews, population coverage, effect sizes | Does the clinical support match the claims your brand wants to make? |
| 4. Consumer Positioning | Mechanism differentiation, consumer awareness, influencer landscape | Is there a clear, differentiated message that segments can own? |
| 5. Supply Resilience | Supplier diversity, quality consistency, GMP and traceability standards | Can the supply chain support multi-year volume growth? |
7. Supplier Evaluation Checklist: Glycine
| Parameter | Target Spec | Why It Matters | Red Flag |
|---|---|---|---|
| Purity | USP/EP/JP grade, ≥98.5% | Baseline quality drives every downstream formulation parameter | Below 98% without explanation |
| Heavy Metals | ICP-MS: Pb≤0.5, As≤1.5, Cd≤0.5, Hg≤0.1 ppm | Retailer QA systems are implementing stricter thresholds | Not tested or only tested via USP <231> |
| Particle Size | D10/D50/D90 range tailored to format | Flowability, compressibility, and blend uniformity | No particle-size testing data provided |
| Density | Bulk 0.45–0.65 g/mL; tapped density with Hausner ratio | Capsule fill weight, powder scoop sizing, and sachet filling | No density data |
| Batch Consistency | 3–5 consecutive CoAs with ≤0.3% assay variation | One good batch is luck; three is a pattern; five is a process | Only the latest batch's CoA provided |
| Residual Solvents | Below ICH Q3C limits | Glycine synthesis can leave solvent residues | Not tested or not disclosed |
| Certifications | GMP + HALAL + KOSHER + ISO 9001 | Different markets and retailers require different certification combinations | Only generic ISO 9001; no GMP certification |
| Supply Redundancy | 2+ qualified production sites or documented backup plan | Single-source dependency creates business continuity risk | Single production site with no redundancy plan |
8. Bottom Line
Recent developments in melatonin's retail environment — CVS restrictions, state-level legislation, international regulatory divergence, and label-accuracy data — are worth monitoring as part of long-term sleep portfolio planning. The data does not suggest melatonin is exiting the market, but it does suggest that procurement teams should evaluate complementary ingredients as a risk-management practice.
Glycine's straightforward regulatory profile and growing — though still developing — clinical evidence base make it a logical addition to the evaluation set for brands that want to diversify their sleep portfolios. It is not a drop-in replacement for melatonin, and brands should avoid positioning it as one. The two ingredients serve different mechanisms, different consumer need states, and potentially different retail channels.
The brands that navigate this transition most effectively will be those that resist the temptation to oversell either ingredient, and instead build portfolios that match ingredient profiles to channel strategies, consumer segments, and regulatory realities — with honest clinical communication at every step.
References
- Lelak K, et al. Pediatric Melatonin Ingestions — United States, 2012–2021. MMWR. 2022. PMID: 35653284.
- Cohen PA, et al. Quantity of Melatonin and CBD in Melatonin Gummies Sold in the US. JAMA. 2023;329(16):1401-1402. PMID: 37097362.
- Thomas DT, et al. Effect of Collagen Peptide Supplementation on Sleep in Physically Active Males. Eur J Nutr. 2024. PMID: 37874350.
- Soh J, et al. The effect of glycine administration on physiological systems in human adults: A systematic review. GeroScience. 2024. PMID: 37851316.
- Nogrady B. Australia issues safety warning on melatonin gummies. BMJ. 2025;391:r2110. PMID: 41057154.