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Our Products.

The Theorem Method is a 3-part haircare system that offers a simple solution to healthier hair.
Our simple 3-part system offers lightweight, nourishing solutions that support healthy hair growth while mending
damaged, brittle hair. Resulting in thicker, longer, stronger, and healthier hair.

Can be used in conjunction with your favorite shampoo and conditioner.

Hypoallergenic

Hypoallergenic

Vegan

Vegan

Gluten-Free

Gluten-Free

No Animal Testing

No Animal Testing

Hypoallergenic

Hypoallergenic

Vegan

Vegan

Gluten-Free

Gluten-Free

No Animal Testing

No Animal Testing

The Method

The Method

The Theorem Method is a 3-part hair care system used to achieve thicker hair from root to tip. These products take a comprehensive approach to strengthening and thickening your hair. Our formulas are precisely pH-balanced to promote a healthy scalp, follicle, cuticle, and hair cortex. Watch as the clinically-proven formulas strengthen and thicken your strands, giving you the length, shine, and fullness you desire. Best used in conjunction with each other but can be used as separate products based on your hair care needs.

Shop Now
Square Root

Square Root

Volumizing Root Serum.

For Fine, Thinning Hair.

Targets hair growth at the root. Thick hair begins with a healthy scalp, and this pH balanced serum plants the seed for dense, gorgeous hair. Square Root fights inflammation-related follicle narrowing, and restores pigment to gray hair naturally (with no dyes). DHT blockers inhibit hormonal hair fall and natural prebiotics promote a healthy, strong skin barrier. Also features a natural alternative to Minoxidil. Minoxidil is the only prescription hair growth ingredient that is FDA approved, but it comes with terrible side effects, which is why we use a safe and natural option instead.

Shop Now
Density

Density

Conditioning Treatment.

For chemically treated, colored or heat damaged hair.

There’s one very important cause of hair loss that is always overlooked: hair breakage. Weak strands with damaged cuticles break easily and hair just can’t grow long or thick. Theorem Density Conditioning Treatment repairs the hair cuticle to promote hair retention. The advanced, silicon-infused formula plumps up hair strands like an injectable filler. Works synergistically with heat to strengthen and thicken hair strands, giving you the length and shine you deserve.

Shop Now
Sugar Pi

Sugar Pi

Damage Repair Oil.

For dry, frizzy hair and split ends.

No matter how fast your hair grows, split ends are an annoying obstacle between you and your long-hair goal progress. This deeply nourishing oil revives and mends split ends, enabling you to grow your hair longer without trimming away damage so frequently. This sustainable, sugar-derived oil repairs damaged cuticles for strong, glossy, frizz-free hair. This naturally-derived, renewable complex is extracted from plant sugar, and microinjects a clinically-proven hair-healing form of Vitamin C into each hair strand to revive broken strands and split ends.

Shop Now

The Method

The Theorem Method is a 3-part hair care system used to achieve thicker hair from root to tip. These products take a comprehensive approach to strengthening and thickening your hair. Our formulas are precisely pH-balanced to promote a healthy scalp, follicle, cuticle, and hair cortex. Watch as the clinically-proven formulas strengthen and thicken your strands, giving you the length, shine, and fullness you desire. Best used in conjunction with each other but can be used as separate products based on your hair care needs.

Shop now

Square Root

Volumizing Root Serum.

For Fine, Thinning Hair.

Targets hair growth at the root. Thick hair begins with a healthy scalp, and this pH balanced serum plants the seed for dense, gorgeous hair. Square Root fights inflammation-related follicle narrowing, and restores pigment to gray hair naturally (with no dyes). DHT blockers inhibit hormonal hair fall and natural prebiotics promote a healthy, strong skin barrier. Also features a natural alternative to Minoxidil. Minoxidil is the only prescription hair growth ingredient that is FDA approved, but it comes with terrible side effects, which is why we use a safe and natural option instead.

Shop now

Density

Deep Conditioning Repair Mask.

For chemically treated, colored or heat damaged hair.

There’s one very important cause of hair loss that is always overlooked: hair breakage. Weak strands with damaged cuticles break easily and hair just can’t grow long or thick. Theorem Density Conditioning Treatment repairs the hair cuticle to promote hair retention. The advanced, silicon-infused formula plumps up hair strands like an injectable filler. Works synergistically with heat to strengthen and thicken hair strands, giving you the length and shine you deserve.

Shop now

Sugar Pi

Damage Repair Oil.

For dry, frizzy hair and split ends.

No matter how fast your hair grows, split ends are an annoying obstacle between you and your long-hair goal progress. This deeply nourishing oil revives and mends split ends, enabling you to grow your hair longer without trimming away damage so frequently.
This sustainable, sugar-derived oil repairs damaged cuticles for strong, glossy, frizz-free hair. This naturally-derived, renewable complex is extracted from plant sugar, and microinjects a clinically-proven hair-healing form of Vitamin C into each hair strand to revive broken strands and split ends.

Shop now

Testimonials

Raquel S.

"Wow’d by the softness of my hair after using it once! "

Tiffany M.

"Smells amazing."

Jess V.

"Smells really good- love how my hair feels after one use."

Hannah L.

"I loved the way it feels on my hair. Super easy to brush through after the shower."

Alissa

"AMAZING PRODUCT! "

Valerie V.

"Loved it - using it since 03/2020"

Rebecca B.

"Loved it - using it since 03/2020"

Alex

"The smell was amazing! Hair was noticeably soothed."

Allison M.

"Loved the way the hair effortlessly blow dried out and have great shine."

Brooke D.

"My long hair is such a pain to brush and after one use I noticd it was smooth and much easier to comb through."

60-Days Guarantee

60-Days Guarantee

We have so much faith in our products that we offer a 60-day, no quibble, money-back guarantee. If you don’t love our products, just send it back to us for a full refund.

Shipping

Shipping

Once your order is confirmed shipped, you will receive your items in 5-7 business day.

Free Shipping

Free Shipping

Spend $50 or more
and shipping is on us!

60-Days Guarantee

60-Days Guarantee

We have so much faith in our products that we offer a 60-day, no quibble, money-back guarantee. If you don’t love our products, just send it back to us for a full refund.

Shipping

Shipping

Once your order is confirmed shipped, you will receive your items in 5-7 business day.

Free Shipping

Free Shipping

Spend $50 or more
and shipping is on us!

Sugar Pi
TH2

Sugar Pi

Damage Recovery oil.

For Dry, Frizzy Hair And Split Ends.

  • Description
  • Ingredients
  • Directions

No matter how fast your hair grows, split ends are an annoying obstacle between you and your long-hair goal progress. This deeply nourishing oil revives and mends split ends, enabling you to grow your hair longer without trimming away damage so frequently. This sustainable, sugar-derived oil repairs damaged cuticles for strong, glossy, frizz-free hair.

Ingredients: C13-15 Alkane, Caprylic/Capric Triglyceride, Squalane, Tetrahexyldecyl Ascorbate, Oryza Sativa (Rice) Bran Extract, Rosmarinus Officinalis (Rosemary) Leaf Extract, Helianthus Annuus (Sunflower) Extract, Tocopherol, Fragrance, Benzyl Salicylate, Limonene, Hexyl Cinnamal, Hydroxycitronellal, Linalool, Alpha-Isomethyl Ionone

Directions: For Oily/Normal Hair: Apply sparingly to damp hair shaft and ends. Avoid roots. Style as usual. For Dry/Frizzy Hair: Apply generously on damp or dry hair, focusing on shaft and ends. When applied to dry hair, it may look wet and greasy. Allow 30 minutes for oil to soak in and soften hair. For split end damage: Apply to just the tips, wet or dry.

Optional Subscribe & Save!

Subscribe to a Monthly Subscription which enrolls you as a Theorem VIP Customer
Save 10% on today’s order + Save 10% on all future orders. You can cancel anytime.

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100% Satisfaction Guaranteed. Free Shipping on Orders over $50

Hypoallergenic

Hypoallergenic

Vegan

Vegan

Gluten-Free

Gluten-Free

No Animal Testing

No Animal Testing

Hypoallergenic

Hypoallergenic

Vegan

Vegan

Gluten-Free

Gluten-Free

No Animal Testing

No Animal Testing

Before and After
Before and After

Testimonials

Raquel S.

"Wow’d by the softness of my hair after using it once! "

Tiffany M.

"Smells amazing."

Jess V.

"Smells really good- love how her hair feels after one use."

Hannah L.

"I loved the way it feels on my hair. Super easy to brush through after the shower."

Alissa

"AMAZING PRODUCT! "

Valerie V.

"Loved it - using it since 03/2020"

Rebecca B.

"Loved it - using it since 03/2020"

Alex

"The smell was amazing! Hair was noticeably soothed."

Allison M.

"Loved the way the hair effortlessly blow dried out and have great shine."

Brooke D.

"My long hair is such a pain to brush and after one use I noticd it was smooth and much easier to comb through."

60-Days Guarantee

60-Days Guarantee

We have so much faith in our products that we offer a 60-day, no quibble, money-back guarantee. If you don’t love our products, just send it back to us for a full refund.

Shipping

Shipping

Once your order is confirmed shipped, you will receive your items in 5-7 business day.

Free Shipping

Free Shipping

Spend $50 or more
and shipping is on us!

60-Days Guarantee

60-Days Guarantee

We have so much faith in our products that we offer a 60-day, no quibble, money-back guarantee. If you don’t love our products, just send it back to us for a full refund.

Shipping

Shipping

Once your order is confirmed shipped, you will receive your items in 5-7 business day.

Free Shipping

Free Shipping

Spend $50 or more
and shipping is on us!

Discover More

Square Root

Volumizing Root Serum.

Shop now

Density

Deep Conditioning Repair Mask.

Shop now

The
Method

Shop now
SugarPi
SKU: TH2
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SugarPi
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