The Leave-In Hair Treatment 50ml

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Healthier hair in a bottle - strengthens, softens, and smooths while reducing breakage and styling damage and supporting natural growth and vibrancy. Powered by TFC8®.

Deluxe Sample(s)

with every purchase over $200
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  • FREE standard delivery on all auto-replenish orders
  • 30 day returns
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Vegan Options Vegan Options
Shot of 'The Leave In Hair Treatment' by Augustinus Bader resting on the clear texture of the product

The Leave In Hair Treatment

Key Benefits
  • Replenishes and smooths strands, boosts shine, tames frizz, and strengthens hair without weighing it down.
  • Helps to support natural hair growth while preventing shedding and breakage.
  • Helps to reverse brittle or weakened hair - renewing strands, improving hair thickness, and noticeably reducing the appearance of split ends.
  • Ultra-nourishing and hydrating seals in nutrients and helps the hair retain moisture for silky locks with a healthy bounce.
  • Softens and detangles hair for easier combing and reduced breakage.
  • Combats damage caused by daily styling, color processing, chemical treatments, and environmental aggressors - for stronger, shinier, more resilient hair.
  • Ingredients that support improved scalp health with soothing, fortifying, and anti-inflammatory properties.
Visible Results
  • 100% agree hair looks and feels healthier after use
  • 90% agree The Leave-In Hair Treatment helps repair hair from heat
  • 97% agree hair feels easier to manage/style after use
  • See clinical and user trials.
  • Ultra-nourishing, and fast-absorbing. Residue-free and does not weigh down hair.
  • Formulated without irritants, allergens, silicones, parabens, or sulfates. Fragrance-free.
  • Suitable for all hair types. Vegan.
  • See ingredients.

How To Apply

Apply a small amount to clean, dry or towel-dried hair. Using fingertips or The Neem Comb, work from the scalp or midlength to the end of hair, focusing on areas of need. Allow hair to dry naturally, or blow dry for an enhanced finish.

  • Use 2 to 3 times per week as needed.
  • For best results, use in conjunction with the Augustinus Bader haircare system: The Shampoo, The Conditioner, The Scalp Treatment, and The Hair Oil.
  • Suitable for all hair types.
Duration: 41s

Clinically Proven Results


Week 0

Week 12

The Leave In Hair Treatment


The Leave-In Hair Treatment increased hair shine by


The Leave-In Hair Treatment increased hair strength by


The Leave-In Hair Treatment increased hair count by


User Proven Results

The Leave In Hair Treatment


agree hair feels and looks healthier after use.


agree hair breakage is decreased.


agree their hair looks smoother.


The Leave In Hair Treatment


agree hair feels easier to manage/style after use.


agree frizz is reduced/tamed.


agree The Leave-In Hair Treatment makes hair shinier.


The Leave In Hair Treatment


agree The Leave-In Hair Treatment detangles hair.


agree The Leave-In Hair Treatment does not leave residue on hair.


agree overall hair quality is improved.


The Leave In Hair Treatment


agree The Leave-In Hair Treatment helps their hair color appear more vibrant.


agree that hair looks and feels renewed and restored after use.


agree The Leave-In Hair Treatment helps reduce styling time.


The Beauty of TFC8®

Our proven results are powered by Professor Bader's TFC8®, Trigger Factor Complex TFC™ - a a carefully crafted blend of high-grade vitamins, lipids, and high-performing, proprietary peptides - and inspired by over 30 years of research, innovation and clinical study.


TFC8® technology guides key nutrients and powerful natural ingredients to the scalp, follicles, and hair, creating and supporting an optimal environment for cellular renewal.


TFC8® turns potent base formulations into smarter, adaptive haircare capable of addressing individualized concerns - such as weak, thinning, or brittle hair, dehydration, shedding and breakage, split ends, frizz, and damage from over-styling, coloring, or external stressors.


TFC8® nourishes and protects, training the hair for the long-term. Resulting in hair that looks and feels healthier, stronger, fuller, and more vibrant.


Key Ingredients

Augustinus Bader haircare is formulated with sustainably-sourced, high potency botanicals and bio-engineered clean actives where possible, to minimize environmental impact.


Powered by our patented TFC8® technology and formulated with potent hair superfoods and anti-oxidants including Neem Extract, Shikakai Extract, and Rambutan Extract to fortify and thicken tresses while actively protecting strands against daily damage.

Tara Fruit Extract & Sunflower Seed Oil Blend

A potent plant-based duo. Naturally protects hair against stressors including heat, pollution, and UV. Restores chemically treated hair, prevents color fading, and helps restore overall resilience and vitality.

Rambutan Fruit Extract

A fruit-derived powerhouse. Revitalizes and protects the scalp and hair follicle against pollution. Hydrates the scalp and delivers free radical protection, for stronger, shinier hair.

Shikakai Extract

A beautifying botanical derived from an herb native to Asia. Naturally softens, detangles and refreshes hair, while keeping the scalp optimally hydrated, preventing flakiness, fortifying strands, and supporting growth.

Neem Extract

A powerful herb used for generations to address hair loss. Helps optimize scalp health while strengthening the hair follicles and encouraging growth.


A vitamin essential to the body’s metabolic processes. Known to help thicken hair, stimulate growth, and prevent shedding.

Argan Oil

A nourishing antioxidant pressed from the argan nut. Packed with essential fatty acids and Vitamin E. Supports new hair growth and guards against visible signs of damage, mending split ends and helping hair look and feel silky and revitalized.

Castor Seed Oil

A naturally rich source of essential fatty acids. Helps fight scalp irritation and hydrates the hair shaft, maintaining elasticity and reducing the risk of breakage.

Oat Kernel Oil

An omega fatty acid and antioxidant powerhouse. Nourishes, soothes, and supports the elasticity of the hair cuticle, while forming a physical barrier to lock in moisture and prevent water loss, keeping strands plump and hydrated.

Vitamin B5

A super-hydrating soother. Moisturizes and softens from root to tip, making hair easier to comb while boosting strength and shine.

Vitamin E

A restorative anti-oxidant. Fends off damage by blocking free radicals, and helps maintain cellular structure, support barrier function, and optimize hydration levels, for soft, vibrant hair.

Bamboo Extract

Improves hair’s moisture retention so it has a healthy, natural shine. It is also known to help soothe the scalp, improve scalp health, and strengthen hair follicles to encourage regrowth.

Just as our hero skin products provide cells with a repair toolbox, The Leave-In Hair Treatment is a complete array of highly effective ingredients that remind hair follicle cells of their innate ability to regrow and renew the hair. The presence of our proprietary technology, TFC8®, ensures that nutrients are delivered precisely where they are needed to awaken the youthful behavior of healthy, thriving hair.

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Discover The Hair Collection

Hydrate, nourish, and renew your scalp and hair with cleanly crafted, high performance haircare.

A model squeezes 'The Leave In Hair Treatment' by Augustinus Bader onto her hand in the shower

Frequently Asked Questions

Is The Leave-in Hair Treatment fragrance-free, vegan-friendly and free from?

The Leave-in Hair Treatment is 100% vegan and free of gluten, GMOs, parabens, silicones, sulfates (SLS, SLES), DEA, fragrance, heavy metals, talc, and petrolatum/paraffin/mineral oil.

Is The Leave-in Hair Treatment packaging recyclable?

Housed in a 100% recyclable tube made from sustainable sugar cane and 100% recyclable cap. Carton and leaflet are FSC-certified and recyclable.

Is The Leave In Treatment safe to use with color treated hair?

Yes, it's a sulfate-free formula design to maintain your hair color. If you have any concerns, we recommend consulting your hairstylist before use.

Is The Leave-in Hair Treatment safe to use during pregnancy?

Yes, The Leave-in Hair Treatment is safe to use in pregnancy and breastfeeding.

Does The Leave-in Hair Treatment have a fragrance?

The Leave-in Hair Treatment is unscented, with no fragrance added.

How long does The Leave-in Hair Treatment last?

The Leave-In Hair Treatment should last around 2-3 months.

How many times a week shoud I use The Leave-in Treatment?

The Leave-in Hair Treatment can be used 2-3 times per week as needed.

Why use both The Conditioner and The Leave-in Hair Treatment?

The Leave-in Hair Treatment boosts hair-healthy properties of The Conditioner, further enhancing hair's natural growth, strength, shine, and resilience. The Leave-in Treatment offers an instant refresh at any point throughout the day.

Can this be used on dry hair or should it only be used on damp hair?

Yes, The Leave-in Hair Treatment can be used on both dry and damp hair.

Can The Leave-in Treatment be used as a heat protector?

The Leave-in Hair Treatment contains multiple powerhouse ingredients that protect against heat and combat damage caused by heat.

Is The Leave-in Treatment safe to use on keratin treated hair?

If you have any concerns, we recommend consulting your hairstylist before use.

Does The Leave-in Treatment can be used as a Sun Care protector?

The Leave-in Hair Treatment contains ingredients that offer natural protection against UV.