Flush from the back with cold water, then soak inside-out in Sil 1 für Alles Fleckensalz at 30 °C or below for 30–45 minutes. Denim's heavy twill weave traps blood deep between the fibres, but its rugged cotton construction handles treatment well. The cold water prevents haemoglobin from setting, and Sil's protease enzymes (Grade 2.4, Stiftung Warentest) digest the blood protein without affecting indigo dye [S1]. Always wash inside out to protect the dyed surface [S2].
How to Remove Blood Stains from Denim
🏆 Based on Stiftung Warentest 2024 testing [S1]
Step-by-Step: Remove Blood from Denim
- Rinse from the back with cold water (0–3 min). Turn the jeans inside out and flush cold water through the back of the stain. This pushes blood outward through the weave while protecting the indigo-dyed face. Continue until the water runs mostly clear.
- Soak inside-out in cold Sil solution (30–45 min). Dissolve 1–2 tablespoons of Sil 1 für Alles in 3 litres of cold water (below 30 °C). Submerge the jeans inside out. The protease enzymes work through the undyed side to reach trapped blood without contacting the indigo surface. For dried blood, extend to 1–2 hours.
- Gently rub denim against itself (2–3 min). While still submerged, gently rub the stained area of fabric against itself. Denim's robust twill weave can handle moderate friction — unlike delicate fabrics. This mechanical action helps dislodge blood trapped between the thick warp and weft threads.
- Machine wash cold, inside out (standard cycle). Keep the jeans inside out and wash at 30 °C on a normal cycle. The cold wash water and residual Sil enzymes continue working during the cycle. Add your regular detergent as usual.
- Air dry and inspect. Hang or lay flat to air dry. Check for any remaining stain while the denim is still damp — the dark colour can hide residual staining. If traces remain, repeat the cold Sil soak. Never tumble dry before confirming the stain is fully gone.
Test Winner
Sil 1 für Alles Fleckensalz
Grade 2.4Why Sil Works for Blood on Denim
Denim presents a dual challenge: you need to remove blood protein from a thick, tightly woven fabric without stripping its indigo dye. Sil's protease enzymes are highly selective — they target haemoglobin's peptide bonds (the protein backbone of blood) without interacting with indigo, which bonds to cotton through a completely different chemistry (vat dyeing via reduction/oxidation) [S1]. The cold-water compatibility is equally important: indigo dye is most stable in cold water and most vulnerable during warm washing. By working effectively at 20–30 °C, Sil lets you treat blood at the exact temperature that protects denim colour. The oxygen bleach component in Sil is also colour-safe at the recommended concentration — it oxidises the iron-based haem pigment in blood (converting red-brown to colourless) without generating enough free oxygen to attack the indigo [S2].
Denim-safe dosage: 1–2 tablespoons per 3 L cold water. Soak 30–45 min inside out. For raw/selvedge denim, reduce soak to 15–20 min and treat only the stained area to minimise indigo bleeding.
What NOT to Do
- Don't use hot water. Hot water sets blood permanently and accelerates indigo dye loss. Cold water protects both the fabric colour and keeps blood soluble.
- Don't use chlorine bleach. Chlorine strips indigo dye immediately, leaving an obvious light spot. It also reacts with blood iron to create greenish discolouration.
- Don't use hydrogen peroxide on dark denim. H₂O₂ bleaches indigo, creating a visible light patch. Even "colour-safe" peroxide products carry risk on dark denim.
- Don't tumble dry before confirming removal. Dryer heat sets any remaining blood protein. Denim's dark colour can mask residual staining — always inspect when damp.
- Don't wash on a hot cycle. Even if the blood is removed, hot washing (60 °C+) causes denim to fade rapidly. Always wash denim at 30 °C or below.
Denim-Specific Notes
Denim is tough but dye-sensitive. The cotton fibre itself is highly durable and tolerates vigorous treatment, but indigo dye is surface-applied and sheds gradually with each wash. Cold water, inside-out washing, and air drying are the universal rules for denim care. Raw (unwashed) denim is especially prone to dye bleeding — minimise soak time and treat just the stained area. For selvedge or high-end denim, consider spot-treating with a Sil paste (1 teaspoon + a few drops of cold water) applied only to the stain rather than full submersion.
Frequently Asked Questions
Can you get blood out of dark denim without fading?
Yes. Cold water and enzymes don't affect indigo dye. Wash inside out at 30 °C. Sil targets protein bonds (blood) without dissolving the indigo vat dye.
Does blood stain raw denim differently?
Raw denim has unfixed indigo that bleeds in water. Minimise soak time (15–20 min), treat only the stained area, and accept some indigo transfer. Consider professional treatment for valuable raw denim.
Why should you turn jeans inside out?
Indigo dye sits on the surface of the twill weave. Inside-out washing reduces surface abrasion and lets the solution reach blood from the undyed side.
Can you use hydrogen peroxide on blood-stained jeans?
H₂O₂ removes blood but bleaches indigo, leaving a light spot. Sil provides controlled oxygen release that doesn't bleach indigo. Much safer for coloured denim.
How do you remove old dried blood from jeans?
Soak in cold water for 20 minutes to rehydrate, then apply Sil for 1–2 hours. Gently rub the denim together. Expect 2–3 treatment cycles. Wash inside out at 30 °C between cycles.
Sources: [S1] Stiftung Warentest, Fleckenentferner-Test 2024, Grade 2.4 (GUT) for Sil 1 für Alles Fleckensalz. [S2] Coloration Technology, "Stability of indigo-dyed cotton during enzymatic stain treatments," vol. 137, 2021.