Lash and Brow Serum
Who can use Line Theory Lash Growth Serum?
Line Theory Lash Growth Serum is designed for anyone looking to support the appearance of longer, fuller, healthier-looking natural lashes. It is especially suited to people whose lashes feel short, sparse, weak, brittle, or damaged from everyday mascara use, lash lifts, extensions, or over-cleansing.
If you are pregnant, breastfeeding, trying to conceive, under medical care, using eye medication, or have an eye condition, we always recommend checking with your medical adviser before use.
What is the difference between Intensive and Precision?
Can I use it if I wear contact lenses or have sensitive eyes?
Many customers with sensitive eyes prefer to choose a prostaglandin-free formula. If sensitivity is a concern, we would recommend starting with our Precision Lash Growth Serum.
As with any product used close to the eye, stop using it if you experience discomfort, redness, swelling, itching, or irritation, and seek medical advice if symptoms continue.
What is prostaglandin?
Prostaglandins are naturally occurring, hormone-like compounds in the body. In lash serums, you may also see prostaglandin analogues, which are synthetic ingredients used in some formulas to encourage the appearance of longer, darker, thicker lashes.
Clinical research supports the lash-enhancing potential of prostaglandin analogues: in a 3-month randomized, double-blind, placebo-controlled pilot study, latanoprost applied in a transparent mascara vehicle significantly increased eyelash length and darkening versus placebo in healthy volunteers.¹
Prostaglandin analogues have been investigated for eyebrow enhancement. In a randomized, double-blind clinical study, bimatoprost—a prostaglandin analogue—significantly increased eyebrow hair density and diameter compared with vehicle over six months.²
¹ Espinoza-Silva JI et al. “A Randomized, Double-Blind, Placebo-Controlled Pilot Study to Evaluate the Efficacy and Safety of Latanoprost for Eyelash Growth in Aesthetic Medicine.” Cosmetics. 2023;10(5):136.
² Suchonwanit P, Chanasumon N, Sriphojanart T. Efficacy and Safety of Bimatoprost 0.01% for the Treatment of Eyebrow Hypotrichosis: A Randomized, Double-Blind, Vehicle-Controlled Study.Dermatologic Surgery. 2019;45(12):1549–1556. doi:10.1097/DSS.0000000000001944.
Do you have a prostaglandin-free lash serum?
Yes. Our Precision Lash Growth Serum is our prostaglandin-free formula, created for customers who want a gentler-feeling lash serum option without prostaglandin ingredients.
It is a great choice if you prefer a prostaglandin-free routine or have sensitive eyes.
Can I use Line Theory Intensive Lash or Brow Growth Serum while pregnant or breastfeeding?
Pregnancy is a medically sensitive time, so we always recommend checking with your doctor, midwife, pharmacist, or medical adviser before introducing any new product around the eye area.
During pregnancy, we would advise considering our Precision Lash Growth Serum or our Precision Brow Serum, which is our prostaglandin-free formula.
Delivery
Which delivery services do you offer?
UK orders are available with standard and express delivery. Available services, timings and costs are shown at checkout for your address.
When will my order arrive?
Standard delivery usually arrives within 2–5 working days, while express delivery usually arrives within 1–2 working days. We will email your tracking details as soon as your order leaves us.
Do you offer international delivery?
At present, we ship to the UK and selected European countries. Available delivery options, timings and costs are shown at checkout.
How Can I Track My Order?
Once your order has dispatched, you will receive a tracking number via email. You can use this number to track your parcel in real time on our website or the carrier’s website
What Should I Do If My Parcel Is Delayed or Lost?
Our Client Care team would be pleased to help. Email hello@linetheory.co.uk, Monday to Friday, 9am–5pm UK time.
Returns
What is Your Return Policy?
We accept returns within 14 days where the item is unused, unopened and in its original packaging. We also offer a 3-Month Moneyback Guarantee; please see our Returns policy for full terms.
How Do I Start a Return?
To initiate a return, visit your customer account on our website or contact our customer support team. We will provide you with a return authorization and shipping instructions.
Do I Have to Pay for Return Shipping?
Return shipping costs may vary depending on the reason for the return. If the return is due to a defect or our error, we will cover the shipping costs. Otherwise, the customer is responsible for return shipping fees.
When Will I Receive My Refund?
Once we receive and inspect your returned item, refunds are typically processed within 5 business days. Refunds will be issued to the original payment method. Please allow additional time for the transaction to reflect in your account.
Can I Exchange an Item Instead of Returning It?
The easiest way to exchange an item is to return it, await the refund and then purchase the item you want in exchange.
Orders
How Do I Place an Order?
You can place an order directly on our website by adding items to your bag and proceeding to checkout. Follow the prompts to enter your shipping and payment details, then confirm your order.
Can I Modify or Cancel My Order After Placing It?
We process orders quickly, but if you need to make changes or cancel your order, please contact our customer support team as soon as possible. Once an order has shipped, modifications may not be possible.
How Do I Check My Order Status?
After placing your order, you’ll receive a confirmation email with a tracking link. You can also log into your account on our website to check the status of your order.
What Should I Do If I Received the Wrong or a Damaged Item?
If you receive an incorrect or damaged item, please contact our support team immediately at hello@linetheory.co.uk. We will arrange for a replacement or refund and cover any return shipping costs if necessary.
Do You Offer Gift Orders or Gift Wrapping?
Yes! We offer gift-wrapping services and the option to include a personalized message. Simply select the gift option at checkout.
Something still on your mind?
Please send us an email at hello@linetheory.co.uk. Our Client Care team replies Monday to Friday, 9am–5pm UK time.
Free delivery on orders over £20
Free delivery on orders over £20