Frequently asked questions

Six ingredients: Water, Glycerin, 1% GHK-Cu (Copper Tripeptide-1), Phenoxyethanol, Palmitoyl Tripeptide-1, and Palmitoyl Tetrapeptide-7. Three clinically studied peptides, two carriers to deliver them, and one gentle preservative. No fragrance, no dyes, no botanical extracts. Every peptide is verified by LC-MS in the finished bottle, at or above label claim, and heavy metals are screened by ICP-MS, at the Mass Spectrometry Core at the University of Illinois at Chicago.

Cleanse, then apply 2-3 drops to your face and neck once or twice a day: morning, night, or both. Wait 60 seconds for it to absorb before you apply anything else, then layer the rest of your routine on top: moisturizer, sunscreen, retinol, or anything else you already use.

Most people notice a difference at around 6 weeks of consistent daily use, which is past the Discovery Size and within one Full Size bottle. Give it a full bottle before you judge the results. Bigger changes take longer, and skin keeps improving with continued daily use, which is also what maintains your results. Individual results may vary.

Both GHK-Cu and Palmitoyl Peptides are generally well tolerated at the concentrations we use. If you are new to copper peptides or have highly reactive skin, patch test on your inner forearm first and start with once-daily use on clean skin. Discontinue if persistent irritation occurs.

Yes. Apply Face Tonic first to clean skin and wait 60 seconds before layering retinol, hyaluronic acid, moisturizer, or sunscreen on top. Many users alternate retinol nights with peptide nights to minimize irritation. Vitamin C is the exception: use it at a different time of day than Face Tonic, or apply it first and wait 20-30 minutes before Face Tonic.

Clinical research on GHK-Cu, Palmitoyl Tripeptide-1, and Palmitoyl Tetrapeptide-7 examined these peptides as focused formulations, not diluted with other active ingredients in the same product. Adding hyaluronic acid or vitamin C reduces the peptide concentrations studied in literature. Use them separately if you like (vitamin C at a different time of day), and read copper peptides and vitamin C for the details.

Yes. If your current serum uses GHK-Cu (Copper Tripeptide-1), it is the same copper peptide, and there is no washout period required. Use PLU in the same slot in your routine.

Generally well tolerated. Research has examined copper peptides across a range of concentrations. If you are stepping up from a very low concentration, start with once-daily use on clean skin, apply before heavier moisturizers, and build up as your skin adjusts.

Five ingredients: Water, Glycerin, 1% GHK-Cu (Copper Tripeptide-1), 1% Acetyl Tetrapeptide-3, and Phenoxyethanol. Two clinically studied peptides, two carriers to deliver them, and a gentle preservative. No fragrance, no dyes, no hormones, no DHT blockers, no botanical extracts. Both peptides are verified at 1% by LC-MS in the finished bottle, at or above label claim, and heavy metals are screened by ICP-MS, at the Mass Spectrometry Core at the University of Illinois at Chicago.

Five ingredients: Water, Glycerin, 1% AHK-Cu (Copper Tripeptide-3), 1% Acetyl Tetrapeptide-3, and Phenoxyethanol. Two clinically studied peptides, two carriers to deliver them, and a gentle preservative. No fragrance, no dyes, no botanical extracts. Both peptides are verified at 1% by LC-MS in the finished bottle, at or above label claim, and heavy metals are screened by ICP-MS, at the Mass Spectrometry Core at the University of Illinois at Chicago.

The copper peptide variant. GHK-Cu (Copper Tripeptide-1) is naturally occurring and has decades of skin and hair research behind it. AHK-Cu (Copper Tripeptide-3) is a synthetic variant with research focused specifically on hair follicle applications. Both formulas are 1% copper peptide plus 1% Acetyl Tetrapeptide-3 in the same clean 5-ingredient base, ingredient preference is the differentiator.

Once a day, part your hair and apply 2-3 drops directly to your scalp in the areas of concern. Massage it in with your fingertips. It works on dry or damp hair. Leave it in and do not rinse. Wait 60 seconds before using other hair products, then style as usual. It takes about 30 seconds, and the steps are the same for GHK-Cu and AHK-Cu Hair Tonic.

Most people notice a difference at around 6 weeks of once-a-day use, which is past the Discovery Size and within one Full Size bottle. Major changes take longer and come from consistent daily use over months, and continued use is what maintains them. Individual results may vary.

Research suggests GHK-Cu may support hair density appearance through scalp health and follicle biology. Our Hair Tonic pairs it with Acetyl Tetrapeptide-3, a biomimetic peptide studied for supporting hair follicle structure. Individual results vary.

It is for you if you have noticed thinning, a widening part, or a hairline starting to recede and want to act on it early; you want a simple five-ingredient formula with no DHT blockers, hormones, or fragrance; and you can commit to once-a-day use for a few months. It is not for you if you expect visible change in under 6 weeks, want a one-bottle fix, or want a DHT blocker or a minoxidil alternative.

Yes. If your hair is fine, thin, or looks weaker than it used to, Hair Tonic is designed to support the appearance of fuller hair with consistent daily use. Its Acetyl Tetrapeptide-3 is a peptide studied for supporting hair follicle structure. Customers with straight, wavy, curly, and coily hair have all reported positive results.

Hair Tonic is not a minoxidil alternative or a DHT blocker. It is a scalp-support formula with no DHT blockers or hormonal ingredients. If you use a treatment such as minoxidil or finasteride, ask your dermatologist about using Hair Tonic alongside it.

No. Hair Tonic is a cosmetic tonic, not a treatment. It is not intended to diagnose, treat, cure, or prevent any condition, and we do not make hair-growth claims. If you are concerned about hair loss, please talk to a doctor or dermatologist.

Anyone. Research on GHK-Cu and Acetyl Tetrapeptide-3 applies equally across genders. We position for men in some marketing for efficiency-focused messaging, but the formulation supports scalp and hair appearance regardless of gender.

Yes. Copper peptide serums can be used on facial hair, including beards, mustaches, and eyebrows. Apply 1-2 drops to the area, and keep it away from your eyes.

Subscribe and save 15% on every order, with free shipping. Deliveries come every 3 weeks for the 10 mL Discovery Size and every 8 weeks for the 30 mL Full Size by default, and you can choose a different interval when you subscribe. Pause, skip, or cancel anytime.

Yes. Subscribe to two different tonics and both are 20% off every delivery. Subscribe to all three and all three are 25% off. Sizes can be mixed and matched. Two of the same tonic count as one item.

You can pause, skip, change, or cancel at any time. Log in to your account and open Subscription management, or use the links in your order confirmation emails. If you need help, email productteam@plulaboratories.com.

Yes. If you are new to PLU, use code START10 at checkout for 10% off your first order. Combined with the subscription discount, your first subscription order is 25% off with one tonic, 30% off with two different tonics, or 35% off with all three. START10 can be used once per customer.

Visa, Mastercard, American Express, Discover, and Diners Club, plus Shop Pay, Apple Pay, Google Pay, PayPal, Amazon Pay, and USDC.

Yes. Email productteam@plulaboratories.com with your order number as soon as you can. We aim to ship orders within 48 hours, Monday to Friday.

GHK-Cu is a naturally occurring copper peptide made of three amino acids (glycine, histidine, lysine) bound to copper. NIH research describes GHK-Cu as both a signal peptide (communicating with skin cells) and a carrier peptide (delivering copper ions studied for tissue processes and collagen production pathways).

A dual-peptide complex working together as matrikine signaling peptides studied for fine lines appearance and skin texture. Many peptide serums contain only one of these or substitute with unrelated peptides; the complete complex requires both.

A biomimetic peptide extensively studied for supporting hair follicle structure. Research suggests it targets the dermal papilla (the foundation of hair follicles) through cellular signaling mechanisms, distinct from hormonal DHT-blocker pathways.

Each peptide works through different mechanisms studied in clinical research. Combining GHK-Cu (signal and carrier peptides) with Palmitoyl Peptides (matrikine signaling) or Acetyl Tetrapeptide-3 (biomimetic follicle support) creates a comprehensive approach through complementary pathways rather than relying on a single peptide.

Clinical research examines these ranges: GHK-Cu 0.5-2%, Acetyl Tetrapeptide-3 0.5-2%. Our formulas use 1% GHK-Cu, 1% AHK-Cu, and 1% Acetyl Tetrapeptide-3, balanced between efficacy studied in literature and tolerance across skin and scalp types. Our Face Tonic also uses Palmitoyl Peptides roughly equivalent to a 3% Matrixyl 3000 solution.

No fragrance, dyes, parabens, sulfates, silicones, essential oils, hormones, or botanical extracts. The Hair Tonics also contain no DHT blockers. Each tonic is five or six ingredients, and every one is listed on the label.

They carry and protect the peptides. Water keeps the tonic water based, so it feels like nothing on skin. Glycerin is a humectant that carries the peptides and helps skin hold on to moisture. Phenoxyethanol is a gentle preservative and the standard choice for water-based cosmetics.

Made in the USA of domestic and internationally sourced components. PLU Laboratories is based in Prospect Heights, Illinois.

No. Our products are never tested on animals.

Our tonics are not vegan certified, so we do not label them vegan. They are never tested on animals, and every ingredient is listed on each product page.

Store at room temperature (60-75 degrees F) in a cool, dry place away from direct sunlight and heat. Avoid bathrooms where temperature and humidity change a lot, and keep the bottle tightly closed. Refrigeration is not required. Unopened, a bottle keeps for 2 years. Once opened, use it within 6 months.

PLU tonics are cosmetics for external use only. Avoid contact with eyes, and stop using if irritation occurs. If you are new to copper peptides or have reactive skin, patch test a small area first. If you have a known skin condition or a copper sensitivity, check with your dermatologist before starting.

Please ask your doctor before adding anything new to your routine while pregnant or nursing.

Postpartum hair can look thinner and feel flat. Hair Tonic is a cosmetic tonic, not a treatment for postpartum shedding, and it is designed to support the appearance of fuller hair. If you are nursing, please ask your doctor before adding anything new to your routine.

Yes. Every batch is tested by the Mass Spectrometry Core at the University of Illinois at Chicago, an independent university lab. You can read the full reports on our Lab Test Results page.

Two things. Each active peptide is measured by LC-MS in the finished bottle to confirm it is at or above its label claim. Each product is also screened for heavy metals by ICP-MS.

Yes. GHK-Cu, AHK-Cu, and Acetyl Tetrapeptide-3 are each independently confirmed at 1% or higher, the concentration we formulate to.

The four heavy metals regulators watch: arsenic, cadmium, mercury, and lead. Results are compared with the FDA's limits for lead and mercury and with Health Canada and EU benchmarks for arsenic and cadmium. All three tonics passed.

We refresh our lab reports as we continue production and grow, so what is posted reflects our current testing. The current reports are the Purity & Concentration Report (July 2026) and the Heavy Metals / Trace Element Report (June 2026).

Shipping is free on every order, with no minimum.

Orders process within 1-2 business days. Domestic shipping takes 3-5 business days after processing. Tracking is emailed automatically once your order ships. Weekend and holiday orders are processed the next business day.

We ship within the United States only through our website. Some international customers can order our products through our Amazon.com listings. We are working on direct international shipping options. Email productteam@plulaboratories.com with your location if you are interested in future direct availability.

Tracking info is emailed automatically once your order ships. If you have not received it within 2 business days of ordering, contact productteam@plulaboratories.com.

We accept returns within 30 days for a full refund, even on opened product. We cannot accept returns beyond 30 days. To start a return, email productteam@plulaboratories.com. Full terms are in our refund policy.

Once we receive and inspect your return, we'll email you the approval status. Approved refunds are issued to your original payment method within 10 business days. Your bank may take a few more days to post the credit.

Yes. If we lower the price of a product you purchased within the previous 7 days, contact productteam@plulaboratories.com and we'll refund the difference to your original payment method. One adjustment per order. See our refund policy for full terms.

Contact us right away at productteam@plulaboratories.com. Every shipment is fully insured, so we may ask for clear photos of the product and packaging, or a brief verification form for our shipping insurer, before we send a replacement or refund. You can also return the item with a prepaid label we provide, and we will issue a full refund when it arrives.

First check around your property, with neighbors, or with your local carrier. Packages are sometimes left in a secure spot or scanned a little early. If it still cannot be found, email productteam@plulaboratories.com. Our shipping insurer requires a brief verification form or signed affidavit, and once it is verified we will send a replacement or refund.