Product Description
Endurance athletes break down connective tissue constantly — tendons, ligaments, cartilage, and bone all absorb the mechanical load of thousands of repetitive footstrikes, pedal strokes, and swim cycles every week. The body rebuilds that tissue through collagen synthesis, and collagen synthesis doesn't happen without lysine.
It's one of nine essential amino acids your body can't produce on its own, and it's a direct structural requirement for building the connective tissue that keeps joints healthy and injuries at bay. Most athletes focus on protein intake and miss this piece entirely.
Thorne Lysine delivers 500mg of pure L-Lysine Monohydrochloride per capsule — the most bioavailable form available, with nothing added.
The Collagen Building Block Athletes Need – Collagen is the primary structural protein in your tendons, ligaments, cartilage, skin, and bone. Lysine is one of the key amino acids required to synthesize it. Without adequate lysine, your body can't produce or repair collagen effectively, and for high-volume athletes putting constant stress on connective tissue, that gap shows up as slower recovery from soft-tissue injuries, persistent joint soreness, and reduced structural resilience over time.
Supports Bone Density Through Calcium Utilization – Lysine plays a direct role in how your body absorbs and uses calcium — the mineral that determines bone density. It helps facilitate calcium transport into bone tissue and reduces urinary calcium loss, making it a meaningful complement to any bone health strategy for athletes who train at high volume on hard surfaces.
Immune Defense When Training Load Is High – Intense training suppresses immune function temporarily, and lysine supports the body's natural defenses during those vulnerable windows. Lysine also helps maintain a healthy balance between itself and arginine — an amino acid that can be exploited by certain viruses when lysine levels run low. For athletes who get cold sores or feel run down during peak training blocks, this is worth noting.
Lysine is primarily found in meat, poultry, fish, dairy, and legumes. Athletes eating high-carbohydrate training diets — or plant-based athletes who rely heavily on grains (which are naturally low in lysine) — are most likely to fall short. Thorne's formula uses the purest form of this amino acid with no unnecessary additives or fillers.
How to Use Thorne Lysine
Daily Dose: Take 1 capsule two to three times daily with food, or as recommended by your healthcare practitioner. Spreading doses across meals supports consistent amino acid availability throughout the day.
For Connective Tissue Support: Research on collagen synthesis suggests that amino acid availability around training — particularly in the 30–60 minutes before loading connective tissue — may improve tissue adaptation. Consider taking one dose before key training sessions.
Pro Tip: Lysine works best when paired with adequate vitamin C, which is also required for collagen synthesis. If you're using lysine specifically for connective tissue support, ensure your vitamin C intake is solid.
- Gluten free
Supplement Facts
60 Servings
Serving Size: One Capsule
Serving Per Container: 60
| Amount Per Serving | ||
|---|---|---|
| % Daily Value* | ||
| L-Lysine (as L-Lysine Monohydrochloride) 500mg | ** | |
* Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.
** Daily Value (DV) not established
Always Happy Promise: Don't like a product? Tell us within 30 days of receipt and we'll make it right and make you happy. Here at The Feed, we want you to love your experience and the sports nutrition products you purchase. If, for any reason, you are not satisfied with your nutrition specific purchase, tell us.
We do not accept returns on food items that have been opened, but we will issue a store credit if you are unsatisfied. In the event of a return, you must first contact us before sending back a return shipment.
Consumable products over $40 receive a 50% store credit. This includes specialty nutrition products such as ketones or supplements/vitamins.
Thorne Lysine FAQ's
Everything you need to know before getting started.
Lysine is one of the key amino acids required to synthesize collagen — the structural protein that makes up tendons, ligaments, cartilage, and bone. Endurance athletes continuously stress these structures, and adequate lysine is required for the body to repair and rebuild them effectively. Lysine is also involved in calcium utilization for bone density and immune defense during the immunosuppressive window that follows hard training.
Lysine is found in meat, poultry, fish, dairy, and legumes. Athletes eating high-carbohydrate diets heavily reliant on grains — or plant-based athletes — are most at risk of insufficient intake, since grains are naturally low in lysine. Even omnivorous athletes may fall short during periods of heavy training when amino acid demands are elevated.
Collagen is built from a specific sequence of amino acids, and lysine is a direct structural component. Your body also uses lysine to form hydroxylysine — a modified amino acid that creates the cross-links giving collagen its tensile strength. Without adequate lysine, collagen fibers are weaker and the repair process is slower. Vitamin C is also required in this process, so pairing lysine with vitamin C intake is worth considering for athletes focused on connective tissue support.
Research on collagen synthesis and amino acid availability suggests that having key amino acids present in the bloodstream around connective tissue loading may improve tissue adaptation. Taking one dose 30–60 minutes before training — particularly before runs, rides, or sessions with significant impact on joints and tendons — is a reasonable strategy.
Plant-based athletes and those eating high-carbohydrate training diets are most likely to fall short of lysine through food alone. Athletes recovering from soft-tissue injuries, those with high training volume on joints and connective tissue, and athletes who experience frequent illness during peak blocks are the primary audiences.